U.S. Senate Minority Leader Mitch McConnell told a conference of rich, politically active conservatives in June that he wouldn't allow votes on the minimum wage and extending unemployment if he becomes majority leader, according to a leaked audio recording.

The Kentucky Republican's campaign didn't deny the recording was accurate and, in fact, said it shows that he is "committed to fighting President Obama's liberal, anti-coal agenda."

The event was organized by billionaire brothers Charles and David Koch, who donate heavily to conservative and tea party causes. The Nation reported that political action committees and people with ties to Koch Industries have contributed at least $41,800 to McConnell during this campaign cycle.

The recording includes passages in which McConnell says he would block votes on issues like raising the minimum wage, extending unemployment benefits and refinancing student loan debt.

"We're not going to be debating all of these gosh darn proposals," he said during the discussion. "These people believe in all the wrong things."

Moments earlier, McConnell had criticized Democrats for favoring campaign finance law, saying "they are frightened of their critics. They don't want to join the tradition in open discourse."

The senator is engaged in a closely contested Senate race against Democrat Alison Lundergan Grimes, and her campaign seized on the recording as proof he is out of touch with Kentuckians.

"Shockingly, Mitch McConnell will do and say anything it takes to secure his grip on personal power, including promising to hurt Kentuckians to benefit billionaires," said Charly Norton, a spokeswoman for Grimes.

Throughout his speech to the group, McConnell criticized "liberal" attempts to pass legislation over the years that would limit the influence of money on politics. He also attacked passage of the campaign finance bill penned by Republican Sen. John McCain and Democratic Sen. Russ Feingold, which sought to cut down on "soft money" given to political parties and limited "issue ads" by outside groups in the days leading up to the election.

"The worst day of my political life was when President George W. Bush signed McCain-Feingold into law in the early part of the first administration," McConnell told the group.

Jonathan Hurst, Grimes' campaign manager, said such a statement is "outrageous."

"There have been many bad days this country has had over the last 30 years and he's saying that's the worst day of his career," Hurst said, noting that during McConnell's tenure, the entire economy almost collapsed in 2008, there have been "bad days in wars" and that McConnell has undoubtedly received reports about job losses in Kentucky.

"It's breathtaking that he would say this is the worst day of his career," Hurst said.

McConnell spokeswoman Allison Moore tried to turn the tables, pointing to an event this year that was attended by Grimes and billionaire hedge fund manager Tom Steyer, who contributes to environmental causes.

"In contrast to Alison Lundergan Grimes' failure to defend Kentucky coal from the EPA behind closed doors with Obama donors, Senator McConnell fights for Kentucky wherever he goes. ... Lord knows what she said to Tom Steyer and anti-coal billionaires when she attended their conference in Chicago," Moore said.

During the Koch event, McConnell also said he would use "riders" attached to federal spending bills to block Obama's agenda on issues ranging from health care to financial services to environmental protection.

This is the second time McConnell has had his words from a private meeting leaked to the public.

In April 2013, Mother Jones posted an audio recording of McConnell and his advisers talking about campaign strategy. Among the things discussed were the mental health issues of actress Ashley Judd, who was considering running against McConnell at the time.

Democratic political consultant Danny Briscoe said he doesn't believe the latest recording has the staying power of the surreptitiously recorded "47 percent" speech by Republican presidential candidate Mitt Romney in 2012, but added Grimes could still use it to her benefit.

Briscoe said that Grimes has already been criticizing McConnell for being "out of touch" and he said McConnell's statements at the Koch event seem to back that up. "I think it gives the Lundergan people a real line of attack on a perceived weakness of McConnell."

Reporter Joseph Gerth can be reached at (502) 582-4702. Follow him on Twitter at @Joe_Gerth.